Safety device for refrigeration systems



'Jan. 30, 1934. MlLLER 1,944,899

SAFETY DEVICE FOR REFRIGERATION SYSTEMS Original Filed April 8, 1930 a 2V 2 w woe/n tot Patented Jan. 30, 1934 FOR REFRIGERATION YSTEMS SAFETYDEVICE s Ernest B. Miller, Baltimore, Md., assignor, by

mesne assignments, to Chester F. Hockley, receiver for The Silica GelCorporation, Baltimore, Md., a. corporation of Maryland ApplicationApril 8, 1930, Serial No. 442,598

Renewed 7 Claims.

This invention relates to refrigeration apparatus frigeration apparatusin which a plurality of 'andmore particularly to that type of reant v Itis a general object of the present invention apor back to liquid.

to provide safety means for a multiple refrigeration system.

re particularly it is an object of this invention to provide means tolimit the quantity of refrigerant which can escape in a given periodfrom a broken or damaged liquid line in a multiple refrigeration system.

important feature of the invention resides in the provision, in amultiple refrigeration system,

of a plurality of secondary receivers, each of such capacity as toprovide the maximum quantity of refrigerant required by the coolingunits associated therewith, together with means for periodically andalternately connecting each secondary receiver to the main receiver andto the pipe delivering liquid refrigerant to the cooling units. s

Other and important objects and features of the invention will be moreapparent to those skilled in the art upon a consideration of the ac- Comp anying drawing and following specification wherein isdisclosed asingle exemplary embodiment of the invention with the understanding,

valve control mechanism for one of the secondary,

receivers; and s Figure 3 is a view in section of the actual valve mechanism.

In providing-refrigeration 1n individual apartments of an apartmentbuilding,

two general systems are in vogue. The first consists in providing acomplete refrigeration unit .for each apartment, which requires,

refrigerator or chest but also an evaporator or cooling unit and someform of mechanism for taking the vapor from and condensing it to theliquid in thecooling unit the cooling unit. The second form makes use ofa refrigerator chest in each apartment, containing a n evaporator orcooling unit, and at some of course, not only a a liquid and returningit to,

April 19, 1933 convenient location a central refrigerating device isarranged and connected by suitable piping to a plurality of the coolingunits. This second system, which the present invention is intended toimprove, is cheaper, of course, than the system where an individual unitis placed in each apartment, but it is subject to danger where therefrigerant is toxic, for, in case of a break in the pipe linessupplying the liquid refrigerant to the evaporators, there is apossibility that all of the 65 refrigerant in the system can bedelivered through this break or leak. This is theprimary danger ofmultiple systems installed according to the present practice.

The present invention contemplates controlling the quantity ofrefrigerant that can leave the system within a given time so that thisdanger is reduced to such proportions as to conform to safety. In fact,it substantially reduces the planger to that comparable with unitsystems where leakage, of course, can take place.

Referring now to the drawing, there is disclosed at 10 any suitablerefrigeration apparatus which may comprise a compressor and condenser aswell as suitable control apparatus; or adsorpso tion apparatus togetherwith a condenser andcontrol devices. The type of apparatus isindependent of the invention which is suitable for any of the presentwell known refrigeration systems. Each. apartment in the building isintended to be provided with a refrigerator containing an evaporatorconventionally represented by the reference character 12. Theseevaporators may be of the flooded type in which coils or tanks arefilled with the refrigerant liquid. The vapor from the liquid is drawnoff through the pipes 13 to the manifold 14 where it is conducted to therefrigeration apparatus 10 and changed from its Vapor phase to a liquidin any of the well known manners. This liquid, hereinafter referred toas the condensate, is then delivered to a receiver 15, as is customary.This receiver acts as a reservoir to always maintain a quantity ofliquid on hand for delivery to the evaporators as required and usuallyunder control of float valves in the evaporators which serve to maintainthe liquid level therein constant.

' To further reduce the amount of refrigerant in the system, the wellknown dye type of evaporator may be substituted for the flooded typeabove described. s

As shown, it is customary to connect several evaporators by means of asingle liquid riser 16. If one of these risers should leak or be brokenin the present systems, all of the liquid in the receiver 15 couldescape through the leak, for it is to be remembered that the refrigerantliquid is such that it will vaporize at atmospheric temperature andpressure.

The present invention provides, in addition to the conventionalapparatus already enumerated, a secondary receiver 18 for each liquidriser 16. each secondary receiver is provided with an inlet valve 19controlling the flow of liquid from the main receiver to the secondaryreceiver, and an outlet valve 20 controlling the flow of liquid from thesecondary receiver to the riser 16.

In Figure 2 the valves 19 and 20 are shown as having their operatingstems connected by means of a centrally pirated lever 21, so arrangedthat but one of the valres can be opened at one time. If the valve 20 isopened, the valve 19 will be closed, and any leak in a riser 16 willonly permit the escape of the liquid in its secondary receiver.

In order that each secondary receiver may be filled with liquidperiodically, means is provided to open the valve 19 for a sufiicientlength of time to fill the secondary receiver and at the same time toclose the valve 20 so that any leak occurring during this change-overcould not exhaust the liquid from the main receiver. Conveniently, thevalves are operated by means of a solenoid 23 connected by means of alink 24 to the inlet valve end of the lever 21. The valve lever isnormally held in the position shown in Figure 2 with the outlet valve 20opened by means of the spring 26, but, when the solenoid is energized byclosing its circuit by tilting the mercury switch 27 so that the mercuryruns down and engages the contacts 28 therein, the valves are reversed,and fluid is permitted to flow into the secondary receiver 18 from themain receiver either by gravity or by the'pressure of the liquid whichvaporizes at temperatures below atmospheric. The switch bulb 27 isperiodically tilted to reverse the position of the valves by means of acam 30 mounted on the shaft 31 of a suitable clock 32 here shown to bean electric clock although it may be of any desired type.

With this arrangement it can be seen that only a limited amount ofliquid refrigerant will be subjected to each riser at any time. Thecapacity of each secondary receiver is determined both by the load onthe riser and the interval of valve operations. For example, let it beassumed that anhydrous ammonia is the refrigerant and that the load oneach riser is 300 pounds ice melting effect per day, or 100 pounds perbox, as shown in Figure 1. Then;

Refrigeration effect of 1 lb. NH3=475 B. t. u.

Refrigerant required per riser per day:

where 144 represents the number of B. t. u.s liberated per pound of icemelted.

Assuming a valve operation interval of 60 minutes, the secondaryreceiver has a capacity of Thus, the maximum amount of ammonia that canpossibly leak out of any break in a riser is 3.79 pounds in one hour.This quantity can be varied by varying the number of risers or changingthe valve shift intervals.

It will be clear that with the valves 19 closed, liquid will bedelivered through the risers by the pressure of the refrigerant in thesecondary receivers and that by the time the liquid in these receiversis used up, a valve shift will take place, and they will be replenishedfrom the main receiver. All of the solenoids controlling the varioussecondary receiver valves can be actuated from a single switch inunison, or separate cams and switches can be provided so that they canbe filled at different times.

In Figure 3 are shown the structural details of the dual valve mechanismin which the valves 19 and 20 are arranged in a single casing to controlthe ports 34 and 35, respectively, where the liquid is fed in' throughthe ports 36 and 37, respectively. The valve stems are surrounded by thecollapsible bellows 38 so that no packing is required, and one of thebellows houses the spring 26 previously referred to.

A complete refrigeration system using an adsorber, a plurality ofevaporators, and an elevated condenser as well as automatic controlmechanism for such system, is shown and described in my copendingapplication Serial Number 398,774, filed October 10, 1929, forRefrigeration system.

Having thus described the invention, what is claimed as new and desiredto be secured by Letters Patent is:

1. In a refrigeration system, in combination, a plurality of evaporatorscontaining a liquid refrigerant, a refrigeration device remote from theevaporators and including a condenserand a condensate receiver, vaporpipe lines associating the low side of the evaporators and therefrigeration device, liquid pipe lines associating the high side of theevaporators and the receiver and means in said last mentioned pipe linesadjacent the receiver to limit the quantity of condensed refrigerantwhich can flow in each under the expanding action of the liquid in apredetermined period of time.

2. In a multiple refrigeration system, in combination, a plurality ofevaporators, a refrigera tion unit comprising means to condense vaporfrom said evaporators, and a condensate receiver, a plurality of pipelines each conveying said condensate from said receiver to one or moreof said evaporators and means time-controlled to limit the quantity ofcondensate which can pass into any one pipe line from the receiverduring a given interval of time.

3. In a multiple refrigeration system, in com bination, a plurality ofevaporators, a refrigeration unit comprising means to condense vaporfrom said evaporators, and a condensate receiver, a plurality of pipelines each conveying said condensate to one or more of said evaporators,a secondary receiver for each pipe line and between it and the mainreceiver, means to normally isolate said main and secondary receiversand means to periodically connect said main and secondary receivers torecharge the secondary receivers. Y

4. In a multiple refrigeration system, in combination, a plurality ofevaporators, a refrigeration 'unit comprising means to condense vaporfrom said evaporators, and a condensate receiver, a plurality of pipelines each conveying said condensate to one or more of said evaporators,a secondary receiver for each pipe line, a valve between each secondaryreceiver and the main a single device for converting vapor from the 156refrigerant to liquid, the combination of a receiver for refrigerantfrom said device, a pipe to deliver said refrigerant from said receiverto one or more of said evaporators and means to limit the flow ofrefrigerant in said pipe in a given interval to the maximum requiredduring that interval by the evaporators connected thereto.

6. In a refrigeration system comprising a plurality of evaporators forliquid refrigerant and a single device for converting vapor from therefrigerant to liquid, the combination of a receiver i'or refrigerantfrom said device, a pipe to deliver said refrigerant from said receiverto one or more of said evaporators, a secondary receiver in said pipenear said main receiver, an inlet valve and an outlet valve for saidsecondary receiver and means to periodically and alternately open one ofsaid valves and close the other.

'7. In a refrigeration system comprising a plurality of evaporators forliquid refrigerant and a single device for converting vaporvfrom therefrigerant to liquid, the combination of a receiver for refrigerantfrom said device, a plurality of pipes each to deliver said refrigerantfrom said receiver to one or more of said evaporators, a secondaryreceiver in each such pipe near the main receiver, each secondaryreceiver being of such capacity as to hold only sufficient liquid forthe maximum demand on its pipe in a fixed period of time, an inlet valvenormally closed and an outlet valve normally open for each receiver, andautomatic means to briefly reverse the positions of said valves once ineach fixed period.

' ERNEST B. MILLER.

